Light weight aggregates formed of fly ash and waste liquor from a pulp mill have been described in the art. For example, in the U.S. Pat. No. 2,833,659 to Bauer, a process is described wherein a small amount of crude waste liquor, such as lignosulphonic acid compounds produced during the manufacture of chemical wood pulp, is mixed with fly ash and clay to form a ceramic material.
In U.S. Pat. No. 2,576,565 to Brown a brick-forming process is described wherein fly ash and slag are wet mixed with a small amount of alkaline earth metal salt of lignosulphonic acid with the latter being used as a binder.
In U.S. Pat. No. 3,862,854 to Zeigerson, halogenated sulfurated lignins are disclosed as flame proofing agents and as ingredients in binders.
These prior art patents describe several techniques for use of lignin produced from wood pulping operations which involve a sulfite or acid process. I have discovered that the use of chlorinated lignins from a kraft or sulfate process has unexpected properties for use in producing light weight aggregate.